/*
 * Copyright (C) 2011 Christopher Probst
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * * Neither the name of the 'FoxNet Codec' nor the names of its 
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.foxnet.codec.pack.reflect;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;

import com.foxnet.codec.Codec;
import com.foxnet.codec.IStream;
import com.foxnet.codec.ObjectOutputChannel;

/**
 * @author Christopher Probst
 */
public abstract class AbstractReflectionCodec<T> implements Codec<T> {

    private static final Comparator<Field> FIELD_COMPARATOR =
	    new Comparator<Field>() {

		@Override
		public int compare(Field o1, Field o2) {
		    return o1.getName().compareTo(o2.getName());
		}
	    };

    // Used to cache fields!
    private final Map<Class<?>, Field[]> fieldCache =
	    new HashMap<Class<?>, Field[]>();

    protected void
	    decodeClass(IStream in, Class<?> targetClass, Object target)
		    throws Exception {
	for (Field field : getSortedFields(targetClass)) {
	    int mods = field.getModifiers();

	    if (!Modifier.isTransient(mods) && !Modifier.isStatic(mods)) {
		field.set(target, in.readObject());
	    }
	}
    }

    protected void encodeClass(ObjectOutputChannel out, Class<?> targetClass,
	    Object target) throws Exception {
	for (Field field : getSortedFields(targetClass)) {
	    int mods = field.getModifiers();

	    if (!Modifier.isTransient(mods) && !Modifier.isStatic(mods)) {
		out.writeObject(field.get(target));
	    }
	}
    }

    protected final Field[] getSortedFields(Class<?> clazz) {
	Field[] fields = fieldCache.get(clazz);

	if (fields == null) {
	    fields = clazz.getDeclaredFields();
	    Arrays.sort(fields, FIELD_COMPARATOR);

	    for (Field field : fields) {
		if (!field.isAccessible()) {
		    field.setAccessible(true);
		}
	    }

	    fieldCache.put(clazz, fields);
	}

	return fields;
    }
}
